What You'll Need
- Frequency analyzer with shaft clamp (for the FLO method) — or
- Spine finder tool with bearing fixture (for the manual method)
- Standard tip weight (165g) or assembled clubhead
- Laser pointer (optional but useful for FLO)
- Permanent marker
- Bench mounting space
Two Methods, One Goal
FLO (Flat Line Oscillation) is the more accurate method — it shows you the shaft's most stable plane by observing how the tip vibrates after release. Spine Finder (bearing method) is faster and uses simpler tools — it locates the stiffest plane by feel.
We use FLO whenever possible. If you don't have a frequency analyzer, the bearing method is the proven alternative.
Method A: FLO (Flat Line Oscillation)
Step 1 — Clamp the Shaft and Add Tip Weight
Clamp the butt end of the shaft in the frequency analyzer with constant pressure. Attach the standard tip weight to the tip (with laser pointer if available).
Step 2 — Pull and Release
Pull the tip down 3–5" perpendicular to the shaft and release smoothly. Watch the tip oscillation:
- Circular or elliptical motion = spine is misaligned with the swing plane
- Straight back-and-forth motion (flat line) = you've found the FLO plane
If using a laser pointer, project the dot on a wall — the path will be obvious.
Step 3 — Rotate and Re-Test
If the first orientation produced an elliptical pattern, loosen the clamp and rotate the shaft 30°–60°. Re-clamp and re-test. Continue rotating until the tip oscillates in a clean flat line.
There are typically two FLO planes per shaft, 180° apart — one is the spine, one is the NBP (Natural Bend Point). Either is stable.
Step 4 — Mark the Plane
Once you've found a flat-line oscillation, mark the top of the shaft at the butt with a permanent marker. This becomes your install reference.
Method B: Spine Finder (Bearing Method)
Step 1 — Secure the Butt
Clamp the butt end of the shaft firmly so it doesn't twist.
Step 2 — Apply the Bearings
Place the spine finder's bearing fixture about 2" from the tip and apply light downward pressure on the shaft.
Step 3 — Rotate Slowly
Slowly rotate the shaft 360°. As it turns, you'll feel the resistance change:
- Resistance peaks = spine (stiffest side)
- Resistance dips = NBP (softest side)
Step 4 — Mark the Spine
Stop at the peak resistance point and mark the top of the shaft at the butt.
Choose Your Alignment Position
The spine can be installed in any consistent orientation. Common choices:
- 12 o'clock (vertical, neutral) — most common, treats spine as straight up. Recommended default.
- 9 o'clock (toward target, RH player) — some builders believe this aligns shaft kick with the target line.
- 3 o'clock (away from target) — alternate position used by some tour fitters.
The position you choose matters less than choosing one and applying it consistently across the entire set. A bag with mismatched orientations will feel uneven club to club.
Install with the Spine Marked
Install the head per the standard re-shaft procedure. Before the epoxy sets, rotate the shaft so the spine mark aligns to your chosen orientation. Verify alignment with the clubface or scoring lines before the epoxy locks the position.
Important Notes
- Modern premium shafts have less spine variation than they did 15 years ago. On top-tier shafts, the difference between aligned and unaligned can be subtle.
- Frequency matching and spine alignment work together. Frequency matching ensures consistent stiffness progression; spine alignment ensures each shaft bends predictably.